Metal-Semiconductor-Metal GeSn Photodetectors on Silicon for Short-Wave Infrared Applications

Abstract

Metal-semiconductor-metal photodetectors (MSM PDs) are effective for monolithic integration with other optical components of the photonic circuits because of the planar fabrication technique. In this article, we present the design, growth, and characterization of GeSn MSM PDs that are suitable for photonic integrated circuits. The introduction of 4% Sn in the GeSn active region also reduces the direct bandgap and shows a redshift in the optical responsivity spectra, which can extend up to 1800 nm wavelength, which means it can cover the entire telecommunication bands. The spectral responsivity increases with an increase in bias voltage caused by the high electric field, which enhances the carrier generation rate and the carrier collection efficiency. Therefore, the GeSn MSM PDs can be a suitable device for a wide range of short-wave infrared (SWIR) applications.

Laser Thermal Processing of Group IV Semiconductors for Integrated Photonic Systems

“…Semiconductor alloys with tin, such as SiGeSn and GeSn, have recently been attracting great interest within the planar photonics community because alloying with Sn (>8 at%) allows for a real direct‐bandgap compound needed for the construction of light sources and photodetectors. [ 64–66 ] However, the fiber community is yet to take full advantage of Sn‐based alloys, with only one example of incorporating Sn as a interfacial metallic layer around a Ge core fiber to date. [ 67 ] Laser processing could be used to complement the fabrication of these fibers, not only by improving the crystalline quality of the core, but also by writing in tensile strains to tune the bandgap postfabrication.…”

“…In recent years, Ge 1− x Sn x alloys have attracted great interest for the fabrication of CMOS‐compatible optoelectronic devices such as photodetectors, light emitting diodes, and lasers [ 64–66 ] because alloying Ge with 8 at% Sn in an unstrained state allows for a true direct‐electronic‐bandgap material. Therefore, various epitaxial growth methods have been developed to grow GeSn alloy thin films on Si substrates.…”

Ge(Sn) growth on Si(001) by magnetron sputtering

“…laser integration). Ge 1x Sn x is a CMOS-compatible IV-IV semiconductor exhibiting interesting properties for infrared photodetector, light emitting diode, and laser fabrication [20][21][22][23][24][25][26]. Furthermore, Ge 1x Sn x alloys can be used for the fabrication of integrated optical amplifier, Gas sensors [27], and high-speed thin-film transistors [28][29], and direct band-gap Ge 1x Sn x alloys are of high interest for solar cells [30].…”

Comparative Study of Si-Ge-Sn Resonant Cavity Enhanced Heterojunction Bipolar Phototransistor (RCE-HPT) under Quantum Confined Stark Effect (QCSE) and Franz Keldysh Effect (FKE) at 1.55 µm

“…Beyond 8% Sn concentration the Ge1-ySny alloy becomes a direct bandgap material [7] and further enhancement of Sn concentration reduces the bandgap and not only increases the absorption coefficient but also shows a red shift [8]. Based on those notable features researchers have developed different types of optical devices such as, light emitting diode [9], LASER [10,11], p-i-n PD [12][13][14][15], metal-semiconductor-metal PD (MSM PD) [16], avalanche photodiode (APD) [17], waveguide PD [18], quantum well infrared photodetector (QWIP) [19][20][21][22] and heterojunction bipolar phototransistor (HPT) [8,[23][24][25][26][27]. Among all those aforesaid PDs, HPT is a potential device.…”